Thread: Google Sandbox

If your website has any duplicate content, or if you used “black hat” strategies to optimize your website, then chances are your website could get caught in Google Sandbox, which for all events and purposes is a filter system program. I found myself there once, and it was frustrating. You therefore have to be very careful, since you could find yourself in the sandbox for a really long time if you ever get caught in there, so you have to be really patient. That’s why it’s best to just stick with the “white hat” SEO strategies. Use long tail keywords for optimization; the sandbox affects competitive keywords only.

But Google has never proved that Sandbox does really exists. So we don't know whether it is or not.